Home
Class 14
MATHS
If x+ (1)/(x)= sqrt3 find x^(67) + x^...

If `x+ (1)/(x)= sqrt3` find
`x^(67) + x^(53) + x^(43) + x^(29) +x^(24) + x^(18) + x^(6) + 3`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we start with the equation given: \[ x + \frac{1}{x} = \sqrt{3} \] We need to find the value of: \[ x^{67} + x^{53} + x^{43} + x^{29} + x^{24} + x^{18} + x^{6} + 3 \] ### Step 1: Find \(x^3 + \frac{1}{x^3}\) First, we will cube both sides of the equation \(x + \frac{1}{x} = \sqrt{3}\): \[ \left(x + \frac{1}{x}\right)^3 = \left(\sqrt{3}\right)^3 \] Using the identity \(a^3 + b^3 + 3ab(a + b)\): \[ x^3 + \frac{1}{x^3} + 3\left(x \cdot \frac{1}{x}\right)\left(x + \frac{1}{x}\right) = 3\sqrt{3} \] Since \(x \cdot \frac{1}{x} = 1\), we simplify: \[ x^3 + \frac{1}{x^3} + 3\sqrt{3} = 3\sqrt{3} \] This leads to: \[ x^3 + \frac{1}{x^3} = 3\sqrt{3} - 3\sqrt{3} = 0 \] ### Step 2: Find \(x^6 + \frac{1}{x^6}\) Next, we can use the result from \(x^3 + \frac{1}{x^3}\) to find \(x^6 + \frac{1}{x^6}\): \[ \left(x^3 + \frac{1}{x^3}\right)^2 = x^6 + \frac{1}{x^6} + 2 \] Substituting \(x^3 + \frac{1}{x^3} = 0\): \[ 0^2 = x^6 + \frac{1}{x^6} + 2 \] Thus, \[ x^6 + \frac{1}{x^6} = -2 \] ### Step 3: Find \(x^6\) From \(x^6 + 1 = 0\), we have: \[ x^6 = -1 \] ### Step 4: Simplify the original expression Now we can express each term in the original expression in terms of \(x^6\): \[ x^{67} = x^{66} \cdot x = (x^6)^{11} \cdot x = (-1)^{11} \cdot x = -x \] \[ x^{53} = x^{52} \cdot x = (x^6)^8 \cdot x^4 = (-1)^8 \cdot x^4 = x^4 \] \[ x^{43} = x^{42} \cdot x = (x^6)^7 \cdot x^5 = (-1)^7 \cdot x^5 = -x^5 \] \[ x^{29} = x^{24} \cdot x^5 = (x^6)^4 \cdot x^5 = (-1)^4 \cdot x^5 = x^5 \] \[ x^{24} = (x^6)^4 = (-1)^4 = 1 \] \[ x^{18} = (x^6)^3 = (-1)^3 = -1 \] \[ x^{6} = -1 \] Now substituting these values into the expression: \[ -x + x^4 - x^5 + x^5 + 1 - 1 - 1 + 3 \] ### Step 5: Combine like terms This simplifies to: \[ -x + x^4 + 3 - 1 - 1 = -x + x^4 + 1 \] ### Step 6: Substitute \(x + \frac{1}{x} = \sqrt{3}\) To find \(x^4\), we can use the relation \(x^2 + \frac{1}{x^2}\): \[ \left(x + \frac{1}{x}\right)^2 = x^2 + 2 + \frac{1}{x^2} = 3 \] \[ x^2 + \frac{1}{x^2} = 3 - 2 = 1 \] Now, we can find \(x^4 + \frac{1}{x^4}\): \[ \left(x^2 + \frac{1}{x^2}\right)^2 = x^4 + 2 + \frac{1}{x^4} = 1 \] \[ x^4 + \frac{1}{x^4} = 1 - 2 = -1 \] Thus, \(x^4 = -1\). ### Final Calculation Substituting back into our expression: \[ -x + (-1) + 1 = -x + 0 = -x \] Since \(x + \frac{1}{x} = \sqrt{3}\), we can conclude: \[ -x = -\left(\frac{\sqrt{3} - 1}{2}\right) \] Thus, the final answer is: \[ \boxed{2 - 2\sqrt{3}} \]
Promotional Banner

Topper's Solved these Questions

  • AVERAGE

    ADVANCED MATHS BY ABHINAY MATHS ENGLISH|Exercise QUESTIONS|115 Videos

Similar Questions

Explore conceptually related problems

If x+ (1)/(x)= sqrt3 find x^(54) + x^(30) + x^(18) + x^(6) + 4

If x+ (1)/(x) = sqrt3 find x^(17) + (1)/(x^(17))

If x+ (1)/(x) = sqrt3 find x^(25) + (1)/(x^(25))

If x+ (1)/(x) = sqrt3 find x^(26) + (1)/(x^(26))

If x+ (1)/(x)= -sqrt3 find x^(25) + (1)/(x^(25))

If x+ (1)/(x)= -sqrt3 find x^(17) + (1)/(x^(17))

If x+ (1)/(x)= sqrt3 find x^(506) + x^(500) + x^(206) + x^(200) + x^(100) + x^(94) + x^(50) + x^(44) + x^(18) +x^(12) + x^(6) + 3

If x+ (1)/(x) = sqrt3 find x^(48)+ (1)/(x^(48))

If x+ (1)/(x) = sqrt3 find x^(117) + (1)/(x^(117))

If x+ (1)/(x) = sqrt3 find x^(102) + (1)/(x^(102))